Maternal Physio - Metabolic Flashcards
By 3rd trimester, maternal BMR is increased by how many percent?
10-20%
- Note:*
- Additional 10% in women with twin gestation
WHO estimate of additional energy demand per trimester
- 1st - 85 kcal/day
- 2nd - 285 kcal/day
- 3rd - 475 kcal/day
Average weight gain
Approximately 12.5 kg or 27.5 lbs
Weight gain
- Normal pre-pregnancy weight
- BMI < 19
- BMI > 26
- Normal pre-pregnancy weight
- 25-35 lb
- BMI < 19
- 28-40 lb
- BMI > 26
- No more than 20 lb
- Summary:*
- 20, 25 or 28-35 depending on BMI
Ideal weight gain by trimester
- T1: 1.5-3 lb gained
- T2 and T3: 0.8 lb/week
Majority of the weight gained from pregnancy comes from:
- Fetus – 3400 g
- Maternal stores (fat) – 3345 g
- Blood and extravascular fluid – 2930g
Factors causing edema (water retention)
- _↑ venous pressure below the level of the uteru_s due to compression of the vena cava and pelvic veins by the gravid uterus
- ↓ in interstitial colloid osmotic pressure
- fall in plasma osmolality of approximately 10 mOsm/kg induced by a resetting of osmotic thresholds for thirst; and
- vasopressin secretion
The minimum amount of extra water accrued during normal pregnancy is ≈ ___ L
- 6.5 L
- 3.5: water content of the fetus, placenta, and amnionic fluid plus
- 3.0: increases in the maternal blood volume and in the size of the uterus and breasts
Carbohydrate metabolism (insulin sensitivity and resistance)
- In the first 20 weeks
- After 20 weeks
- In the first 20 weeks
- Insulin sensitivity ↑ in first half of pregnancy
- Lower fasting glucose levels allow for glycogen synthesis and fat deposition
- After 20 weeks
- Insulin resistance develops and plasma insulin levels rise
- Higher levels of both insulin and glucose stimulate utilization of glucose and lipids for energy
As a result of insulin, what is a common finding in pregnant women?
- mild fasting hypoglycemia
- postprandial hyperglycemia
- hyperinsulinemia
Why is pregnancy-induced state of peripheral insulin resistance occur?
To ensure a sustained postprandial supply of glucose to the fetus
Hormones that mediate postprandial hyperglycemia
-
Progesterone and estrogen
- mediate insulin insensitivity
- Placental lactogen
- increase lipolysis → liberation of free fatty acids → tissue resistance to insulin
The optimal time to screen for glucose intolerance
26–28 weeks gestation
Normal pregnancy state is:
- Hyperlipemic
- Glycosuric
- Anabolic
Concentrations of lipids, lipoproteins, and apolipoproteins in plasma
- During pregnancy
- After delivery
- They increase during pregnancy
- They decrease after delivery
The storage of fat occurs primarily during which stage of pregnancy?
Mid-pregnancy
Note: Fat storage declines or ceases during the 3rd trimester
Where are fats deposited and its implication? What hormone is responsible?
- Deposition
- mostly in central rather than peripheral sites
- Rationale
- it becomes available for placental transfer during the last trimester when fetal growth rate is maximal along with essential fatty acids requirements
- Mechanism
- progesterone acts to reset a lipostat in the hypothalamus, and at the end of pregnancy, the lipostat returns to its previous nonpregnant level, and the added fat is lost
Leptin
- Disease associated with deficiency
- Disease associated with elevation
- Secreted by
- Adipose tissue, placenta
- Action
- Play a role in body fat and energy expenditure
Etymology:
- leptos - “thin” ⇒ “the hormone of energy expenditure”
- lept_in_ - _in_hibiting hunger
Leptin
- Disease associated with deficiency
- Disease associated with elevation
- Disease associated with deficiency
- Anovulation
- Infertility
- Disease associated with elevation
- Preeclampsia
- GDM
Etymology:
- leptos - “thin” ⇒ “the hormone of energy expenditure”
- lept_in_ - _in_hibiting hunger
Ghrelin
- Secreted by
- Action
- Secreted by
- Stomach in response to hunger
- Action
- Cooperates with leptin in energy homeostasis modulation
How much sodium and potassium are retained in normal pregnancy? Are these increased or decreased?
- 1000 mEq of sodium and 300 mEq of potassium
- Decreased
What happens to serum calcium level during pregnancy? Describe the mechanism.
Decreased; lowered plasma albumin concentration and, in turn, the consequent decrease in the amount bound to protein
What happens to serum magnesium level during pregnancy? Describe the mechanism.
Decreased; pregnancy is actually a state of extracellular magnesium depletion
